What value do ASTM, ASCE, and ASTM add to developing engineering standards? For instance, is tech certification in concrete inspection, an ASTM standard, even necessary for mechanical and civil applications such as oil well completions or highway pours?

They have a lot to do with it, but it depends on where you are at. It is vastly easier for me to write a spec that refers to a specific standard than to write pages of verbiage describing what I want. If we all start out with a specific expectation (a standard) then I only have to lay out specifics.

You can't be suggesting that you don't specify the aggregate mix baesd on SHRP standards for instance in today's world for something as "mundane" as pavement.